Meteors rain down on the earth every hour of every day. Most of these are hardly larger than a grain of rice or a pea. The majority are little more than particles of dust, 10 to 40 micrometers (0.0004-0.0016 inch) in size. The average one is scarcely a quarter of the width of a human hair. The atmosphere makes short work of the larger ones. The remainder of these small meteors—-called "micrometeorites"—-are perpetually sifting down to the surface. Ten thousand tons of them every day.

And they fall on everything. Which means that you can easily collect some for yourself. The great French astronomer-artist, Lucien Rudaux, was one of the first to do this and made something of a hobby of it. He took a great many photos of the microscopic meteorites he found.

Line the cookie sheet with the plastic wrap. Fold the edges of the wrap under the sheet, so it won't blow away. Place it outdoors in a place where nothing blocks the sky and the sheet is protected from the wind. Let the sheet remain outdoors for at least a week. When you bring it back inside, the plastic will be covered with all sorts of debris. If it has rained, it will be full of water, too. Straining the water through a sieve will help get rid of any large debris, such as leaves and bugs. Carefully run the magnet through what remains. A piece of paper wrapped over the end of the magnet will make it easier to remove whatever sticks to it. (Another method is to fasten a couple of magnets over the downspout of a rain gutter, so that rain water will pour over them. After a couple of weeks, check the magnets.)

You will find some small particles sticking to the magnet. These are the remnants of meteoroids that disintegrated in the upper atmosphere. They stick to the magnet because most meteoroids have iron and nickel in them. Look at the particles through the magnifying glass or microscope. What do they look like? Compare them to the ones in the photo Rudaux took. And have fun!